Organosilicon compounds which have been used to improve the adhesion of organic inorganic composite materials include known various silane coupling agents such as .gamma.-chloropropyl trimethoxysilane, .gamma.-aminopropyl trimethoxysilane, .gamma.-gIycidoxypropyl trimethoxysilane, .gamma.-methacryoxypropyl trimethoxysilane and .gamma.-mercaptopropyl trimethoxysilane. However, since these silanes have only one functional carbon group, they cannot be used as a crosslinking agent between organic polymers. There exists a need for organosilicon compounds having two functional carbon groups for use in the improvement of adhesion between organic and inorganic materials.